Glossary Of Terms - F

Fainting collapse Fall False positive Fats monounsaturated fat hydrogenation
saturated fat low-fat spreads Fatty acids omega-3 omega-6 cis fatty acids
trans fatty acids hydrogenated vegetable oil Femoral artery Fibrillation Finometer tilt testing First aid
Fitness from volume of oxygen Flavin Flavonoid Folic acid Forearm elbow Formula in chemistry
Free radical Fructose, sugar Furosemide

F1 and F2 are first and second year after qualifying as a doctor.

Fainting See under Collapse.

Fall See under Collapse.

False positive. A false positive result is when a test shows a patient has something wrong, but in fact the patient does not have that.

Tests are not always fully sensitive and thus fully correct. Technical problems – operator error, or poorly performing reagents, and/or factors specific to the organism or patient may result in a false positive.

Where a diagnosis is elusive or uncertain, the situation may need tests repeating and/or several different tests. Diagnostic uncertainty can occur for example in immune-compromised patients such as transplant recipients where infectious processes sometimes don’t show.

A false negative is when a test does not show that a patient has something wrong, but in fact the patient does have that wrong.

Fats. People need some fat for health; otherwise their body systems could not process the fat-soluble vitamins A, D, E and K. See Fatty acids for the various types of fats.

The recommendations below are aimed at preventing or reducing the risks of heart disease. They do not apply to children under five years old or to people training for sports or who are ill. See also reducing undesirable fats under Diet. See also Fat content of cheeses.

Fatty acids are compounds of carbon, hydrogen and oxygen that form part of a lipid molecule. Many derivatives are formed by modifying the chain of carbon and other atoms in each molecule. Some fatty acids are needed for health. Fatty acids are not the same as fats.

Monounsaturated fat is found in olive oil, groundnut oil, and rapeseed oil – and is believed to be good. See mono- under organic chemistry.

In monounsaturated spreads derived from these, the oil is changed from a liquid into a spread by adding hydrogen atoms at appropriate places on the fatty acid molecules, called hydrogenation. The resulting margarine, which may be called reduced-fat spread or hydrogenated vegetable oil, is claimed to be fairly good for health; but is not as good as the original unprocessed olive oil, groundnut oil, or rapeseed oil, because some cis may have been changed to trans by the heating.

Mono, Olivio, Olive Gold, and Blue Band are such margarines. Mono- means one.

Polyunsaturated fat is believed to be good for health. It is found in corn oil, sunflower oil, safflower oil, sesame, and soya oil and oily fish. Poly- means many. Polyunsaturated molecules have long carbon chains with many double bonds, such as omega-3, cis, and trans below.

Saturated fat is in dairy fat, red meat fat, coconut oil, and palm oil. These are mainly hard at room temperature, and come from animal sources – eg butter, lard, fat on meat, or cream. These are believed to be generally bad for people with any heart related disease or risk of it.

More generally, because they are believed to be bad for all adults, saturated fats should be eaten only occasionally or in small quantities. Some vegetable fats are also high in saturates – eg many hard margarines, and non-dairy cream.

Low-fat spreads usually contain half or less fat than butter or ordinary margarine, and therefore fewer calories. They may contain saturated or polyunsaturated fats – check the label.

I remember in the early 1960s my father explaining linolenic acid (an omega-3 explained below), linoleic acid (an omega-6 explained below), and arachidonic acid (an omega-6).

Linolenic acid Alpha Linolenic Acid is one of three forms of omega-3 polyunsaturated fatty acids – see Polyunsaturated fat. Alpha linolenic acid is a structure that cannot be produced by the body and so is needed from the diet.

The other two forms of omega-3 are:
- eicosapentaenoic acid EPA, with 20 carbon atoms and five cis double bonds – its name is derived from the Greek eicosa for 20, and from penta the Greek for five; and with the first cis double bond at the third carbon from the omega end); and
- docosahexaenoic (or docosahexaneoic) acid (DHA). Docosahexaenoic acid is the main structure in brain tissue. It is an omega-3 polyunsaturated fatty acid with 22 carbon atoms – found almost only in fish and marine animal oils. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end.)

Linoleic acid is an unsaturated omega-6 fatty acid.

Arachidonic acid is an omega-6 fatty acid, and is synthesized from linoleic acid. The human body can do that synthesis, but cats cannot! It forms the basis of some prostaglandins. The formula is C20H32O2 – it has a chain of 20 carbon atoms, with 32 hydrogen atoms, and two oxygen atoms.

The above omega-3 and omega-6 fatty acids are a group of long-chain polyunsaturated fatty acids, and known to reduce the risk of heart disease. They are lipid-regulating; and they lower the level of cholesterol LDL and triglycerides in the blood. So after a heart attack they reduce the risk of further heart attacks and increase overall survival. They can reduce serum cholesterol levels and have anticoagulant properties.
Most people’s diets in the UK and most developed countries contain more than enough or too much omega-6 fatty acid, and do not contain enough omega-3 fatty acid. Obviously there are some people who know about these and deliberately adjust their diet eg by having oily fish (explained under Diet). The recommended daily intake of omega-3 is 0.45g. The UK average in 2004 was only 0.1g.
The name comes from omega-3 polyunsaturated fatty acids having the first carbon–carbon double bond in the n−3 position in the hydrocarbon chain – ie occurring between the third and fourth carbon atoms from the methyl end of the molecule – the end most distant from the carboxylic-acid COOH group. Similarly omega-6 polyunsaturated fatty acids have the first carbon–carbon double bond in the n−6 position in the hydrocarbon chain – ie occurring between the sixth and seventh carbon atoms from the methyl end of the molecule.

Omega-3 fish oil is a neutraceutical, a food that provides health benefits. Eating fish has been reported to protect against late age-related macular degeneration, a common eye disease. The maximum benefit appears to be from eating fish at least once a week. The main food sources are fresh or frozen oily fish: salmon, pilchards, tuna, sardines, trout, mackerel, and herring. Unfortunately, tins of fish of these kinds contain less omega-3, since the processes of preparing the tinned products remove or change some of the omega-3. Several manufacturers produce Omega-3 as capsules.

Since the 1960s or earlier some people have known that eating oily fish once or twice per week helps prevent narrowing of the arteries and CHD.

The claimed beneficial effects of omega-3, as well as those above, include: lowering blood pressure, inhibiting breast cancer, reducing inflammation in rheumatoid arthritis, and improving bone growth. The claimed benefit that it improves brain function is probably not proven and may be wrong.

Omega-6 fatty acids occur in terrestrial plants, including safflower oil, corn oil, and evening primrose oil, which is a rich source of linoleic and arachidonic acids. The name omega-6 is derived similarly to omega-3 as explained above.

Unfortunately the human body cannot synthesize n−3 fatty acids. But the body can form long chain 20-carbon unsaturated n−3 fatty acids (like EPA) and 22-carbon unsaturated n−3 fatty acids (like DHA) from the short chain eighteen-carbon n−3 fatty acid alpha-linolenic acid. The human body conversion process is not very efficient. Unfortunately this is affected by the possibility of a similar process on omega-6 – of which as above we have too much in our diet.

Fatty acids - Cis and trans. Cis is healthy, trans is not.

Cis. The natural form of double bond between two carbon atoms in a fat is a cis structure. Generally fatty acids with a cis structure are believed to be good for people. To imagine a cis structure: form a horizontal V with the index and middle finger of each hand, and touch corresponding fingertips together. Tuck in your third and fourth fingers – making fists except for the touching fingers, and extend your thumbs towards your chest so the tips of your thumbs are as far apart as possible. Each fist represents a carbon atom, joined together by a double bond – your touching fingers. Your thumbs each represent a bond, and each such bond goes to a group of atoms in an unsaturated compound. Imagine also a bond to a hydrogen atom coming off the back of each hand. This is a cis structure. Here cis means the two unsaturated compound groups of atoms are both on the same side of the double bond – the same side as your body.

But trans fatty acids are generally believed to be bad for health.

Trans-fatty acids, also called trans fats, are unsaturated fatty acids with at least one double bond that is a trans structure molecular configuration.

They occur naturally in small amounts in dairy products and meat. The food label may say hydrogenated vegetable oil. Trans-fatty acids occur in some: margarines, cakes, biscuits, pastries, and fast foods. The amounts in different makes and types of similar foods such as margarines vary substantially.

Trans fatty acids are also formed by hydrogenation of vegetable oils – a process that converts vegetable oils into semisolid fats – sometimes done to extend the shelf life of processed foods. Trans fatty acids are formed when vegetable oils are artificially hardened, ie processed into a solid fat by heating. The main sources are blocks of hard vegetable margarines and bought cakes and pastries. They should be limited – especially if your blood cholesterol is high.

For a trans structure: keep your left hand where it was for cis, and turn over just your right hand – palm away from your body, so each index finger now touches the opposite middle finger tip, and your right thumb points away from your chest. The trans has the two compound groups of atoms on opposite sides of the double bond – the left one is towards your body and the right one away from you. Trans means across, on the other side, through, or beyond.

A 2004 research study compared people that ate foods with more trans-fatty acids with others in a control group who ate foods with less trans-fatty acids. The study found that people who ate more trans-fatty acids generally had: higher LDL, lower HDL, higher risk of thrombosis, and more heart disease – all these are undesirable!

Femoral artery. Each femoral artery is a main artery for blood flow to a leg. It comes near the skin at the crease at the groin.

Ferrous means the iron is divalent (a valency of 2) in the compound. Ferric means the iron is trivalent (a valency of 3) in the compound. See Heam.

Fibrates See fibrates under Lipid-lowering agents.

Fibrillation is a local uncontrollable twitching of the heart wall fibres or parts of muscles, and/or irregular beating. See Atrial fibrillation, and Ventricular fibrillation.

Fibrinogen is a blood-clotting agent. In research trials high levels were found to be statistically associated with an increased risk of adverse heart conditions such as CHD.

Finometer tilt testing. Hospital staff investigate a patient who has blacked out and where the cause cannot be diagnosed by other tests. They try to make it happen again under controlled conditions.

The patient lies settled in a darkened room on a bed tilted say 45º, while blood pressure, ECG, and perhaps other variables are continuously recorded – giving the changing trends on a beat-by-beat basis. Eg when the patient is tilted the patient’s BP changes before he or she feels unwell.

The BCPA in 2003 bought a Finometer machine costing over £15,000 for Papworth Hospital. This was then the only such machine in East Anglia that can do full blood tests with continuous monitoring, so doctors and other hospitals send such patients to Papworth.

First aid is the first help given by the first person at the scene or incident. It is not complicated and does not need much equipment. First Response means essentially the minimum knowledge as a short course of up to about four hours.

Carers and relatives of people who may need help should do a short first aid course if possible, giving the knowledge and confidence to deal with likely situations.

It is not feasible to explain first aid fully here. People need to go on a short course.

See ambulance for when to call an ambulance.

First aid course. A four-hour first aid course includes training and practice at dealing with a variety of casualty situations, including doing CPR on a dummy. These skills may help prevent further injuries, help recovery, and save lives.

To attend a course, enquire locally at St. John Ambulance, St. Andrew's Ambulance Association, or the British Red Cross. A telephone directory usually gives the number.

On eight occasions over the last 30 years, I have been the first or nearly the first person to reach a casualty or stop at a road traffic accident. Most of these accidents involved a casualty needing first aid and an ambulance to hospital. One was a heart attack – the patient was taken to hospital and recovered.

The three first aid principles are remembered by PPP

Preserve life

Prevent deterioration – by treating any life-threatening conditions such as shock and bleeding

Promote recovery – by preventing danger, reassuring each casualty, putting them in an appropriate position, and eg protecting them from cold, wet, and wind.

The carer or first aider should continually say to the patient what you are doing, aware that the patient may hear and see even if they are not responding.

The first person to arrive at an accident or emergency should do an initial survey – danger, response, airway, breathing and circulationDRABC.

Avoid danger – check the safety of everyone, make the situation safe, not rush in until sure that it is safe to approach – eg gas, electricity, fumes, traffic, spilt fluids eg poisons, fire, dangerous building, rocks that might fall, tide, and/or people who might make it worse.

Don't move a casualty unless they are in some danger.

Assess the situation – prioritise if there are several casualties, get bystanders to help as appropriate, get help, ask the casualty questions eg whether they have pain and where, listen to what they say.

At a road traffic accident, as soon as you know how many casualties and the severity of their injuries – eg whether conscious or unconscious, and whether likely to be stretcher cases – get someone to phone for an ambulance and tell them a brief description of the injuries. See ambulance for when to call an ambulance. They should come back to say they have done it.

If the casualty does not immediately speak or cry, speak loudly into each of their ears, eg 'Are you all right?' and gently shake their shoulders. Maybe say your first name, eg 'I'm ...'

If no response to that, check the casualty's level of response. Shout a command such as 'open your eyes' into each ear in case they are deaf. If no response, check whether they are breathing by putting your cheek near their mouth & nose to feel their breath, listening, and watching their chest and abdomen for movements.  

If not breathing, open their airway by tilting the head back, and then as below.

If not breathing, call 999 for an ambulance as above and do Cardiopulmonary resuscitation.

If they are breathing, but not responding to voice, say what you are doing in case they can hear you though unable to speak, look for signs such as fractures or other injuries or conditions, maybe put them in the recovery position.

Also see levels of consciousness. See ambulance for when to call an ambulance.

Fish. See oily fish under Fatty acids and under Diet.

Fitness from volume of oxygen Fitness can be measured by the volume of oxygen an athlete can use while exercising at maximum capacity. VOX2 max is the maximum amount of oxygen in millilitres used in one minute per kilogram of body weight. Those who are more fit have higher VO2 max values and can exercise more intensely.

One can increase one's VO2 max by working out at an intensity that raises one's heart rate to 65% to 85% of one's heart rate maximum for at least 20 minutes three to five times a week. The original research paper is by Bruce, RA: Multi-stage treadmill test of maximal and sub maximal exercise (1972).

Flavin has three meanings:

1  another name for quercetin.

2  a heterocyclic ketone, formula C10H6N4O2, that forms the nucleus of some natural yellow pigments, eg riboflavin.

3  any yellow pigment based on meaning 2.

Flavone has two meanings:

1  a crystalline compound occurring in plants, with formula C15H10O2.

2  any of a class of pigments derived from meaning 1.

Flavonoid. There are six classes of flavonoids: flavonols, flavones, isoflavones, flavanones, flavan-3-ols and anthocyanins.

Quercetin and epicatechin are the major flavonoids in our diet – their main sources being red wine, cocoa, onions, tea, (and particularly) apples – ROTA. Quercetin is metabolised very quickly by the intestine and liver, and is not actually found in human blood.

Flavonoids in the diet lower heart disease risk. See an apple a day.

Folic acid is an essential vitamin needed to avoid anaemia and to control homocysteine.

Forearm See Forearm under Elbow.

Formula in chemistry means the chemicals in a molecule of a compound expressed in symbols (that are abbreviations for elements and/or simple structures), numbers (how many such), and implying the structure. Plural formulae.

The atoms are denoted by single or double letters – eg H is hydrogen, C is carbon, N is nitrogen, O is oxygen, Na is sodium, Cl is chlorine.

Also – represents a single bond, and = represents a double bond.

So eg NaCl is sodium chloride, which is common salt. Also H2O has two hydrogen atoms and one oxygen atom, and is water. The oxygen atom has two bonds and each hydrogen has one bond. So it is structurally like H–O–H but always written H2O.

Also, –OH is a shorthand for –O–H, which means an oxygen atom and a hydrogen atom; and the oxygen has two bonds, one to the rest of the molecule and the other to the hydrogen which has one bond.

In many formulae most of the bonds are omitted, and people trained in chemistry understand.

Formulary is a book giving the details of drugs and other health products – eg for pharmacists, medics, dentists, and manufacturers.

Free radical. See Antioxidant.

Furosemide is a generic name diuretic, see diureticbrand names Froop, Lasuix, Frusol. Also see Bumetanide.


This information was created and edited by Richard Maddison for the BCPA.
Copyright © 1997-2019 The British Cardiac Patients Association, and/or Richard Maddison.
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First published in this form 2002, and updated 2005, 2007, 2008, 2011, 2012, 2013, 2017.
All rights reserved. No part of this work may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, without written permission from the BCPA Head Office.

We give permission for copies to be stored and made within the BCPA and any UK hospital; and these hospitals may give printed but not electronic copies to patients provided the source and copyright is acknowledged on the copies - eg include the page footer.

Authors, sources and acknowledgements

The main sources are BCPA Journal published articles, other information from authors, and publicly available documents and websites. In many cases the journal articles give sources and further information than the Glossary entries.

Parts of the wordings under ECG and Echocardiogram are adapted with permission from BUPA's health information resources, available at

We hope we have thanked everyone.

Richard Maddison

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